In Qubes 3.1 this management stack makes it possible to conveniently control
system-wide Qubes configuration using centralized, declarative statements.
Declarative is a key word here: it makes creating advanced configurations
significantly simpler (the user or administrator needs only to specify what
they want to get, rather than how they want to get it).
This has already allowed us to improve our installation wizard (firstboot) so
that it now offers the user ability to easily select various options to
pre-create some useful configurations, such as e.g. Whonix or USB-hosting VMs.